This proposal represents a continuation of our studies into the immunobiology of the lipopolysaccharide of Neisseria gonorrhoeae. These studies will be accomplished through the following specific aims. Secretions from men with gonococcal urethritis and secretions and endocervical tissue from females with gonococcal cervicitis will be studied to define the histopathology of gonorrhoeae using electron microscopic methods and to define the antigenic characteristics of lipopolysaccharide present in human gonococcal infection. This will be accomplished using monoclonal antibodies in immunofluorescent, immunoelectron microscopic and ELISA systems. 2) The chemical nature of the gonococcal LPS antigens which are present in human disease and which are targets for the human immune response will be defined. The oligosaccharide chains containing these antigens will be isolated and the chemical constituents of these antigens will be determined. Oligosaccharide chains shown to contain antigens relevant to the human immune response will be conjugated to a variety of gonococcal cell surface proteins including fragments from enzymatic digestion of pilus and protein l. The human immune response to gonococcal lipopolysaccharide will be studied to define the LPS sites against which bactericidal antibody is directed in normal human serum, in patients with genital gonorrhoeae and in patients with gonococcal PID and disseminated infection and to define the evolution of the human immune response to gonococcal LPS which occurs in genital and extra-genital gonococcal infection.